Avoid encoding in LogResponseObject when we are not going to use it

Signed-off-by: Davanum Srinivas <davanum@gmail.com>

Kubernetes-commit: e418ee3a92ca6c670d26f775b0f669e8a5fe233c

pkg/audit/request.go

@@ -171,7 +171,7 @@ func LogRequestPatch(ctx context.Context, patch []byte) {
 // will be converted to the given gv.
 func LogResponseObject(ctx context.Context, obj runtime.Object, gv schema.GroupVersion, s runtime.NegotiatedSerializer) {
 	ac := AuditContextFrom(WithAuditContext(ctx))
-	if ac.GetEventLevel().Less(auditinternal.LevelMetadata) {
+	if ac.GetEventLevel().Less(auditinternal.LevelRequestResponse) {
 		return
 	}
 

pkg/audit/request_log_test.go

@@ -0,0 +1,259 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package audit
+
+import (
+	"context"
+	"io"
+	"strings"
+	"testing"
+
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
+	auditinternal "k8s.io/apiserver/pkg/apis/audit"
+)
+
+func TestLogResponseObjectWithPod(t *testing.T) {
+	testPod := &corev1.Pod{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "v1",
+			Kind:       "Pod",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-pod",
+			Namespace: "test-namespace",
+		},
+		Spec: corev1.PodSpec{
+			Containers: []corev1.Container{
+				{
+					Name:  "test-container",
+					Image: "test-image",
+				},
+			},
+		},
+	}
+
+	scheme := runtime.NewScheme()
+	if err := corev1.AddToScheme(scheme); err != nil {
+		t.Fatalf("Failed to add core/v1 to scheme: %v", err)
+	}
+	codecs := serializer.NewCodecFactory(scheme)
+	negotiatedSerializer := codecs.WithoutConversion()
+
+	// Create audit context with RequestResponse level
+	ctx := WithAuditContext(context.Background())
+	ac := AuditContextFrom(ctx)
+
+	captureSink := &capturingAuditSink{}
+	if err := ac.Init(RequestAuditConfig{Level: auditinternal.LevelRequestResponse}, captureSink); err != nil {
+		t.Fatalf("Failed to initialize audit context: %v", err)
+	}
+
+	LogResponseObject(ctx, testPod, schema.GroupVersion{Group: "", Version: "v1"}, negotiatedSerializer)
+	ac.ProcessEventStage(ctx, auditinternal.StageResponseComplete)
+
+	if len(captureSink.events) != 1 {
+		t.Fatalf("Expected one audit event to be captured, got %d", len(captureSink.events))
+	}
+	event := captureSink.events[0]
+	if event.ResponseObject == nil {
+		t.Fatal("Expected ResponseObject to be set, but it was nil")
+	}
+	if event.ResponseObject.ContentType != runtime.ContentTypeJSON {
+		t.Errorf("Expected ContentType to be %q, got %q", runtime.ContentTypeJSON, event.ResponseObject.ContentType)
+	}
+	if len(event.ResponseObject.Raw) == 0 {
+		t.Error("Expected ResponseObject.Raw to contain data, but it was empty")
+	}
+
+	responseJSON := string(event.ResponseObject.Raw)
+	expectedFields := []string{"test-pod", "test-namespace", "test-container", "test-image"}
+	for _, field := range expectedFields {
+		if !strings.Contains(responseJSON, field) {
+			t.Errorf("Response should contain %q but didn't. Response: %s", field, responseJSON)
+		}
+	}
+
+	if event.ResponseStatus != nil {
+		t.Errorf("Expected ResponseStatus to be nil for regular object, got: %+v", event.ResponseStatus)
+	}
+}
+
+func TestLogResponseObjectWithStatus(t *testing.T) {
+	// Create a status object to test ResponseStatus handling
+	testStatus := &metav1.Status{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "v1",
+			Kind:       "Status",
+		},
+		Status:  "Success",
+		Message: "Test status message",
+		Reason:  "TestReason",
+		Code:    200,
+	}
+
+	scheme := runtime.NewScheme()
+	err := metav1.AddMetaToScheme(scheme)
+	if err != nil {
+		t.Fatalf("Failed to add meta to scheme: %v", err)
+	}
+	scheme.AddKnownTypes(schema.GroupVersion{Version: "v1"}, &metav1.Status{})
+	codecs := serializer.NewCodecFactory(scheme)
+	negotiatedSerializer := codecs.WithoutConversion()
+
+	ctx := WithAuditContext(context.Background())
+	ac := AuditContextFrom(ctx)
+
+	captureSink := &capturingAuditSink{}
+	if err := ac.Init(RequestAuditConfig{Level: auditinternal.LevelRequestResponse}, captureSink); err != nil {
+		t.Fatalf("Failed to initialize audit context: %v", err)
+	}
+
+	LogResponseObject(ctx, testStatus, schema.GroupVersion{Group: "", Version: "v1"}, negotiatedSerializer)
+	ac.ProcessEventStage(ctx, auditinternal.StageResponseComplete)
+
+	if len(captureSink.events) != 1 {
+		t.Fatalf("Expected one audit event to be captured, got %d", len(captureSink.events))
+	}
+	event := captureSink.events[0]
+
+	if event.ResponseObject == nil {
+		t.Fatal("Expected ResponseObject to be set, but it was nil")
+	}
+	if event.ResponseStatus == nil {
+		t.Fatal("Expected ResponseStatus to be set for Status object, but it was nil")
+	}
+	if event.ResponseStatus.Status != "Success" {
+		t.Errorf("Expected ResponseStatus.Status to be 'Success', got %q", event.ResponseStatus.Status)
+	}
+	if event.ResponseStatus.Message != "Test status message" {
+		t.Errorf("Expected ResponseStatus.Message to be 'Test status message', got %q", event.ResponseStatus.Message)
+	}
+	if event.ResponseStatus.Reason != "TestReason" {
+		t.Errorf("Expected ResponseStatus.Reason to be 'TestReason', got %q", event.ResponseStatus.Reason)
+	}
+	if event.ResponseStatus.Code != 200 {
+		t.Errorf("Expected ResponseStatus.Code to be 200, got %d", event.ResponseStatus.Code)
+	}
+}
+
+func TestLogResponseObjectLevelCheck(t *testing.T) {
+	testCases := []struct {
+		name         string
+		level        auditinternal.Level
+		shouldEncode bool
+	}{
+		{
+			name:         "None level should not encode",
+			level:        auditinternal.LevelNone,
+			shouldEncode: false,
+		},
+		{
+			name:         "Metadata level should not encode",
+			level:        auditinternal.LevelMetadata,
+			shouldEncode: false,
+		},
+		{
+			name:         "Request level should not encode",
+			level:        auditinternal.LevelRequest,
+			shouldEncode: false,
+		},
+		{
+			name:         "RequestResponse level should encode",
+			level:        auditinternal.LevelRequestResponse,
+			shouldEncode: true,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Create a test object
+			testObj := &corev1.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "test-pod",
+					Namespace: "test-namespace",
+				},
+			}
+
+			// Create audit context with the specified level
+			ctx := WithAuditContext(context.Background())
+			ac := AuditContextFrom(ctx)
+			ac.Init(RequestAuditConfig{Level: tc.level}, nil)
+
+			// Create a mock serializer that tracks if encoding was attempted
+			mockSerializer := &mockNegotiatedSerializer{}
+
+			// Call the function under test
+			LogResponseObject(ctx, testObj, schema.GroupVersion{Group: "", Version: "v1"}, mockSerializer)
+
+			// Check if encoding was attempted as expected
+			if mockSerializer.encodeCalled != tc.shouldEncode {
+				t.Errorf("Expected encoding to be called: %v, but got: %v", tc.shouldEncode, mockSerializer.encodeCalled)
+			}
+		})
+	}
+}
+
+type mockNegotiatedSerializer struct {
+	encodeCalled bool
+}
+
+func (m *mockNegotiatedSerializer) SupportedMediaTypes() []runtime.SerializerInfo {
+	return []runtime.SerializerInfo{
+		{
+			MediaType:        runtime.ContentTypeJSON,
+			EncodesAsText:    true,
+			Serializer:       nil,
+			PrettySerializer: nil,
+			StreamSerializer: nil,
+		},
+	}
+}
+
+func (m *mockNegotiatedSerializer) EncoderForVersion(serializer runtime.Encoder, gv runtime.GroupVersioner) runtime.Encoder {
+	m.encodeCalled = true
+	return &mockEncoder{}
+}
+
+func (m *mockNegotiatedSerializer) DecoderToVersion(serializer runtime.Decoder, gv runtime.GroupVersioner) runtime.Decoder {
+	return nil
+}
+
+type mockEncoder struct{}
+
+func (e *mockEncoder) Encode(obj runtime.Object, w io.Writer) error {
+	return nil
+}
+
+func (e *mockEncoder) Identifier() runtime.Identifier {
+	return runtime.Identifier("mock")
+}
+
+type capturingAuditSink struct {
+	events []*auditinternal.Event
+}
+
+func (s *capturingAuditSink) ProcessEvents(events ...*auditinternal.Event) bool {
+	for _, event := range events {
+		eventCopy := event.DeepCopy()
+		s.events = append(s.events, eventCopy)
+	}
+	return true
+}